1. Field of the Invention
The present invention relates to the field of joining wooden fittings and more particularly joining together stair rail wooden fittings.
2. Description of the Prior Art
A typical stair rail has a main body whose angle of slope is relatively constant throughout its length. However, at both the top and the bottom of the stairs, there are fittings with portions whose slope differs from the slope of the main body of the rail. In order to have a free flowing rail, the fittings at the top and at the bottom of the rail must be accurately cut to meet and mesh with the main body of the rail. The prior art method for-accomplishing the cutting and the joining of stair rail fittings requires that a separate special tool, called a pitchblock be prepared for each stair rail.
As shown in FIG. 6, the pitchblock 3 is essentially a triangular template in which the hypotenuse of the right-angle triangle is called the "pitch line," the bottom horizontal side is referred to as the "run" side, and the vertical side is called the "rise" side. The angle between the pitch side and the run side corresponds to the angle of incline of the stair rail. The length of the run side corresponds to the unit run of the staircase being constructed. The length of the rise side corresponds to the unit rise of the staircase being constructed.
As shown in FIG. 2, the fitting for the stair rail at the bottom of the staircase is referred to as a "starting fitting" such as the starting fitting 1. In order to cut the starting fitting 1 so that a smooth joint can be made between the stair rail and the starting fitting, as shown in FIG. 3, the starting fitting is placed on a flat surface so that the level portion of the starting fitting lays substantially flat, as shown in FIG. 7 with the starting fitting 2. Then, as shown in FIG. 7, the pitchblock 3 is placed with the run side level on the flat surface and moved so that a point on the pitch side comes into contact with a point on the upturned portion of the starting fitting 2. At that contact point in order to scribe the line to be cut, the pitchblock is turned 90.degree. so that the rise side is substantially level on the flat surface. The pitchblock is then moved so that the pitch side of the pitchblock is aligned with the mark made on the fitting as shown in FIG. 8. With the pitchblock in this position, a line is scribed along the fitting corresponding to the pitch side of the pitchblock. The starting fitting is then held securely and cut squarely on the line that has been scribed on the fitting. Since the pitchblock is originally fashioned to correspond to the particular rail and stairs being worked with, the starting fitting 2 as now cut will meet and mesh with the stair rail 6 main body in a smooth free-flowing manner as shown in FIG. 3.
As shown in FIGS. 1 and 4, the fitting to be joined to the top of the main body of the stair rail is commonly referred to as "gooseneck fitting." As shown in FIG. 5, since a gooseneck fitting is at the top of the stairway, the angle at which it is cut is equal to the complement of the angle of incline of the stair rail. According to the prior art method, in order to achieve this cut accurately, the pitchblock is used in a similar fashion, but initially the rise side of the pitchblock, as shown in FIG. 9, is placed on the flat surface to mark a point of contact between the pitchblock and the curved portion of the gooseneck fitting 4. Once the point of contact has been marked, the run side of the pitch block is placed on the flat surface, as shown in FIG. 10, and the pitchblock is moved to a position such that the pitch side of the pitchblock coincides with the point of contact marked on the fitting. At this point a line is scribed on the fitting using the pitch side of the pitchblock as a ruler. The gooseneck fitting is then taken and held securely and cut squarely on the line which has been scribed on it. It should then mesh and join smoothly with the rail 5 as shown in FIG. 4.
There are numerous problems associated with the prior art method and apparatus scribed above. The method requires a fairly sophisticated, capable, and well-trained craftsman. It requires numerous precise measurements and operations. Since the desired end result is a smooth joining of the fitting to the rail, even a small error in measurement or marking can result in an unacceptable result. The method requires a separate pitchblock for each particular stair rail; and, although, there is a normal range of angles of incline for stair rails, usually 30.degree. to 37.degree., there is an infinite variety of stair rail angles within the 30.degree. to 37.degree. range. Also, even in the unlikely event that a craftsman has a set of pitchblocks that accommodates the 30.degree. to 37.degree. range, if he is confronted by an unusual angle of incline outside of this range, he must develop a new pitchblock on the spot. Further competence and accuracy is required to perform the separate step of holding and cutting the fitting once it has been marked.